I use Windex on a soft bristled toothbrush. NEVER allow any lens cleaner or glass cleaner containing ammonia (like Windex) to come into contact with the lens. This especially applies to lens coatings made prior to the mid 70s and to naturally bloomed lenses. The coatings back then were soft and were not fused to the glass (they hadn't yet learned to bake them) and the ammonia may eat up your lens coating.

Soft toothbrush and Windex, followed by shoe polish (followed by a shine sponge -- or Scuff Guard -- IF the original finish was supposed to be high gloss). You can use a leather protectant, if you wish, but NOT Armorall. Armorall makes the surface slippery and you don't want to drop your camera.

A mild soapy water solution applied with a soft-bristled toothbrush, followed by saddle soap follwed by a silicone-based leather protectant, followed by shoe cream. Don't let the leather get too wet and soak through or the glue or shellac that attaches it to the camera may let go. If the leather is snagged (little bits of leather sticking up), I'll attempt to stick the snags back down with a 50/50 solution of bookbinder's glue and water, sparingly applied with a toothpick.

I use a slightly thinned solution of black leather dye, followed by a sealant. If it has a few really small bits missing, a black lacquer pen can be used to fill in the missing bits. If necessary, layers are built up until it looks natural.

If you have pinholes, replacement is your best option. It is the ONLY permanent one. Bellows can be patched, but the patch will always be weak and will eventually start leaking light again. The best patching material I know of is bookbinder's glue mixed with lampblack. If you can't find bookbinder's glue, mix one drop of liquid soap with a bottlecap of Elmer's glue and add the lampblack. The dish soap makes the glue more flexible and so it will last a little longer. Black acrylic paint is also reported to work well, and remain flexible.

Never-Dull metal polish. If the aluminum has oxidation stains, Alumabrite (sold in marine hardware stores) will sometimes get them out (keep it well away from the glass). If not, you'll have to resort to #0000 steel wool.

Never-dull metal polish. A chemical polish like Tarn-X can be used for especially stubborn stains on brass. Keep all chemical polishes away from the glass (most contain acids that can etch glass or eat away the balsam cements used in mounting them).

If an automotive chrome polish won't get it out, the only things you can do are learn to live with it, remove the chrome (and go to a brass finish) or get the part re-chromed. If you opt to go for the brass finish, a coat of clear lacquer will help you avoid having to polish the brass every two weeks or so.

The aforementioned paint pens from Micro Tools will sometimes work. Micro Tools. Most times you will still be able to see a very clear delineation between new and old paint though. If so, you'll have to strip all the paint off, prime, and repaint. Micro Tools also sells a "camera paint" that matches most original finishes. As a side note, Krylon Ultra Flat Black spray paint is good for replacing the flat black paint on the inside of the camera. Spray some into a can and apply it with a brush. An alternative is a flat black paint called "stove paint" that is found in most hardware stores. If you are going to completely repaint your camera, and if you have used an enamel paint, you'll want to bake it afterward, to harden the paint. No, you don't put your camera in the oven. When the paint is dry, you put it in a box with a 100-watt lightbulb for about an hour.

There are a variety of methods for cleaning lenses. This is the one I use, because I think it poses the least risk of scratching the lens. In the photography forum, I've been seeing some threads on lens cleaning that recommend lens tissues. This is a cheap and convenient way to do it, but it is also risky. Tissues trap dust and grit between lens and tissue and it is all too easy to scratch the lenses. Some lens tissues, meant for eyeglasses, are actually mildly abrasive and can scratch coated lenses with no help from trapped grit. Microfiber lens cloths are safer, but still not 100% safe. So how do you do it?

Well, first you go over it with a blower and lens brush, to remove as much grit as possible.

Next you are going to need some solvents. Commonly used solvents used in camera restoration (and lens cleaning) are:

Denatured alcohol, used to remove tar (from cigarettes, or pine pollen) and detriorated light seal material (sometimes found stuck to rear lens elements). Do NOT use rubbing alcohol; it will work, but it is not a benign solvent and it can attack some balsam cements used to glue lens elements together.

Naphtha (Ronsonol lighter fluid), used to remove grease and oils (naphtha is REALLY good for fingerprints).

Distilled water, used to remove everything else.

These are all benign and won't harm your camera if you just keep them out of the electronics and don't actually SOAK the camera in them.

One other special solvent: a 50/50 mix of hydrogen peroxide and ammonia, used to kill and remove lens fungus.

Then you get a big box of Q-tip cotton swabs. Dampen a swab with your solvent of choice, and start in the center of the lens, working outward. A little solvent goes a long way, so you want your swab to be damp, not wet. Use gentle pressure, not much more than the weight of the Q-tip. Don't scrub, but let the solvent do the work. Twist the swab as you go, so that a fresh surface is kept in contact with the lens and any grit is lifted away from the glass, not rubbed against it. You'll go through quite a few Q-tips. I generally go over my lenses two or three times with each solvent.

When you use the naphtha, you may notice a haze forming on your lens as it dries. Don't panic; this is a GOOD thing. The haze is oil and grease that has been hydrolyzed (made water soluble). The naphtha itself leaves no residue. When you go over it with the distilled water, it will remove the haze.

Yes, there really is a type of fungus that can grow on lens coatings. The fungus secretes an acid that can, in time, etch the underlying glass. If it hasn't etched the glass, fungus and mildew can be killed and removed with a 50/50 mix of hydrogen peroxide and ammonia. There are several methods of cleaning up lens fungus, but this one is the best I know of for killing the spores, so it doesn't come back. At the same time, you need to give the camera a very thorough overall cleaning and replace the light seals, so you get the spores hiding elsewhere in the camera.

Mildew in a leather camera case cannot be killed short of soaking it in bleach (which would damage the case). You can knock it back in any of several ways, but it always comes back. It is best to just get a new case. Mildew can sometimes be found in bellows too. Replacement is your best option. "New old stock" Kodak and Zeiss bellows occasionally come up for auction on ebay, and these will fit most cameras. For those who REALLY don't want to do this, or who can't afford it, you can try "painting" the bellows (inside and out) in the aforementioned 50/50 solution of hydrogen peroxide and ammonia. This is not really a good idea (the glue may come loose that attaches the inner liner), but you have little to lose. I've also heard some people say that Listerine mouthwash will kill it, and they say they've had good results, but I haven't tried this one yet and can't vouch for it.

These are not high precision optics, but are just plain plate glass. Windex or other commercial glass cleaner on a Q-tip will do fine.

A note of warning -- If you are cleaning the focusing screen on a TLR or a view camera, be aware that the framing guidelines on some cameras will wash off! An extra fine point Sharpie marker will put them back if you haven't washed them totally away.

Now a word about the viewfinders on box cameras and those little pyramidal viewfinders on folding cameras: Again, these are not precision optics. Basically, they just show you where the camera is pointed. An old watchmaker's trick, used for brightening and removing scuffs from watch crystals, is to rub it with a little toothpaste on your finger. This will remove crud from a viewfinder that you didn't even know was there. It works especially well for brightening the plastic viewfinder lenses on box cameras. It will work on glass too, but it takes longer. Do NOT try this on the taking lens though, because that IS a precision lens, and toothpaste is abrasive.

First blow the loose crud out with a can of compressed air or a blower. DON'T use the kind of compressed air that comes in a spray can from the photo shop. I am talking about the kind you refill yourself with an air pump. Don't let the nozzle get too close to any semisilvered mirrors (what you would find in a rangefinder camera) or you risk blowing the silvering off. This should get rid of most of the loose crud. For bits of deteriorated tar-like light seal material, a Q-tip cotton swab dampened with denatured alcohol (found in hardware stores) will remove them. Use naphtha (Ronsonol lighter fluid) to remove hardened lubricant and the crud stuck in it. If you are going to relubricate, use a synthetic gun oil or sewing machine oil and be very sparing with it. Oil tends to spread to other parts (where you don't want it to go) and that is why you are having to clean it up. A very little goes a long way in a camera and too much can cause far more problems than too little. You should use no more than you can lift on the point of a needle, and only apply it to friction surfaces. The only places you might use more is on the focusing rod of some TLRs (the Ciroflex, for example) and on the focusing helical of an SLR (which uses lithium or silicone grease, is in the lens, and doesn't really belong here in an article on cleaning and lubing cameras)

the one that is the most fraught with peril
Focusing screens in SLRs are plastic Fresnel lenses more often than not. They are pretty delicate and are easily scratched (the plastic is not particularly hard). DON'T use anything that is harder than the plastic screen to clean them. This includes brushes with plastic bristles. DON'T use anything that will rub grit against the screen (like a cloth or lens paper). I use an artist's brush I found at an art supply store. The handle is made of plastic. I heated it with a butane lighter and bent the handle at a right angle, near the tip, so I can get at the focusing screen with it better. First I gently brush at it for a while (dry) to loosen and remove any grit. Then I dampen the brush with distilled water (just damp, NOT wet) and go over it several times. Just gently brush at it, don't scrub, cleaning your brush every so often, until it is clean.

There are several kinds. (A) Semisilvered mirrors: For semisilvered mirrors (ones you can see through, like in a rangefinder), the only thing that should ever touch them is a puff of air. If you touch them, the silvering WILL come off. It is very delicate and will stick to your fingers better than it will to the glass. (B) Front silvered mirrors: The mirrors in some cameras are front silvered (the silvering is on the front of the glass instead of the back). If you don't know, always assume the mirror is front silvered. Although these are not as fragile as the semisilvered mirrors, you REALLY don't want to scrub at them, because the silvering is a lot softer than the glass and can be easily damaged. I use Q-tips and a solvent (after blowing them with compressed air) and I let the solvent do the work, with little more pressure than the weight of the swab. I twist the swab as I go, in order to lift grit away from the mirror and keep a clean surface against the glass (I go through a LOT of swabs). The solvents I use are distilled water (for dust and dirt) and denatured alcohol or naphtha (for removing bits of crumbled light seal material). (C) Reverse silvered mirrors: Reverse silvered mirrors have the silvering on the back of the glass. These can be cleaned in the same way that you clean a lens.

The best is to disassemble the shutter and clean every part individually, then reassemble. However, that is well beyond the skill level of most people.

The next best method is to remove just the glass and then submerge it in a solvent in a vibrator cleaner. It is important to remove the glass first because vibrating cleaners are known to cause micro-fractures of the surface of the glass. Most people don't have access to a vibrating cleaner though and so they won't be able to use this method either.

Use a lens spanner wrench to remove the rear lens element, so you can see the aperture iris and the shutter blades. Set the aperture on it's widest setting and clean the back of the blades with a cotton swab dampened with naphtha (Ronsonol lighter fluid). Work the shutter a few times, get a new swab, and clean it again. Alternate between moist swabs and dry swabs, mopping up the lighter fluid (and dissolved oil) with the dry swabs. Keep doing this until there is no hint of oil or grease left on the blades. The blades working together will transfer any grease or oil from the front of the blades (that you can't reach) to the backs of others (which you CAN reach), so you should be able to eventually get it all. It takes a while. As long as you're at it, do the aperture blades too. When done, DO NOT LUBRICATE THE BLADES!!!!! Leaf shutters are designed to run dry (no lubricant). The blades will stick together and the shutter won't work if they are lubricated.

Circuit board cleaner (sold at Radio Shack) can be used to clean most electronics (bushes and variable resistors, for example). Always remove the battery first. The circuit board cleaner may be non-conductive, but the crud you're cleaning up (and that is suspended in it) probably isn't.